REXUS/BEXUS

Support: Launch capacity on stratospheric balloon, as well as logistical and technical support.

Description: REXUS/BEXUS - Rocket and Balloon Experiments for University Students

The REXUS/BEXUS programme allows students from universities and higher education colleges across Europe to carry out scientific and technological experiments on research rockets and balloons. Each year, two rockets and two balloons are launched, carrying up to 20 experiments designed and built by student teams.

Rexus

REXUS experiments are launched on an unguided, spin-stabilised rocket powered by an Improved Orion Motor with 290 kg of solid propellant. It is capable of taking 40 kg of student experiment modules to an altitude of approximately 100 km. The vehicle has a length of approx. 5.6 m and a body diameter of 35.6 cm.

BEXUS experiments are lifted by a balloon with a volume of 12 000 m³ to a maximum altitude of 35 km, depending on total experiment mass (40-100 kg). The flight duration is 2-5 hours.

Bexus

The REXUS/BEXUS programme is realised under a bilateral Agency Agreement between the German Aerospace Center (DLR) and the Swedish National Space Board (SNSB). The Swedish share of the payload has been made available to students from other European countries through a collaboration with the European Space Agency (ESA).

EuroLaunch, a cooperation between the Esrange Space Center of the Swedish Space Corporation (SSC) and the Mobile Rocket Base (MORABA) of DLR, is responsible for the campaign management and operations of the launch vehicles. Experts from ESA, SSC and DLR provide technical support to the student teams throughout the project.

REXUS and BEXUS are launched from SSC, Esrange Space Center in northern Sweden.

Supporters & Sponsors

Team SmartFish GmbH

Support: Being interested in reentry and knowing there was an interesting new approach to aircraft design made by Team Smartfish GmbH and its CEO Koni Schafroth we set up a collaboration to use the unique shape on our glider and thereby test the concept as a first step in an stratospheric environment.

Description: SmartFish

SmartFish differs from conventional aircraft by its innovative aerodynamic design, while relying on standard technologies for building materials and propulsion.

Backed through results from preliminary wind tunnel tests and scale model flight data we are convinced that a SmartFish aircraft has many potential advantages over conventional aircraft of comparable size and propulsion system, such as improved efficiency (per freight transported) and a much bigger internal volume. Because of the simplicity of the design we anticipate that manufacturing costs (for design and assembly), maintenance costs, and operating costs will be potentially lower than those for conventional aircraft.

The SmartFish proof of concept will be realized in collaboration with following companies: Extra (world leader in aerobatic aircraft) for system integration and test flights, Leichtwerk for interpretation statics and dynamics, LTB Borowski for composite manufacturing, Liebherr Aerospace for Landing Gear System development, DLR (German Aerospace Center) for flutter analysis and inlet optimization, RUAG Aerospace for wind tunnel testing, and EPFL, the Swiss Federal Institute of Technology for verification of different simulation results.

Fieldview Animation of Smartfish

Fieldview of Smartfish with AOA 25

April 12th 2011 @ 01:00AM

Successfull maiden flight of electric "StageI-Prototype"

After a rather breathtaking launch followed a good flight and shuttle like landing.

Consider that the modell weighs 1,2kg with an wingspan of only 60cm in this configuration. That's alot, but includes ballast to accomodate for the missing autopilot and camera weight in this flight.

Successfull maiden flight of "StageI-Prototype"

Today we successfully launched our first Protype. The flight was an unpowered, manually radiocontrolled glide to verify the Center of Gravity (CG) and test general flight behaviour.

"StageI-Prototypes" are constructed in styroform, whereas the final flight model will be made of glas- and carbon-fibre reinforced plastic (GRP/CRP). "StageI" is intended for autopilot development and testing.

A bunch of Hardware

Today we received a nice bundle of hardware. It contains a Microprocessor board, static and dynamic pressure sensors, an inertial measurement unit (short: IMU; combination of accelerometers and gyros) and a GPS receiver.

The hardware and related software is from the “Ardupilot” community, a UAV dedicated sub community of the open source project “Arduino”. “Arduino” is a standardized, Atmel microcontroller based board, allowing a quick and easy entry to the whole microcontroller subject.

The challenge for us will be to adapt the hard- and software for the very special needs of our task. This will be done by testing under harsh environments generated for example in a thermal/vacuum chamber. The stratospheric “Bexus” balloon can reach heights up to 35km, which is already part of “Near Space”. “Near Space” is a zone starting at the height of 30km and reaching up to the border of “Space” defined at 100km. The temperature in the balloons mission profile can drop as far down as -90°C and the air is so thin that the sky is already as black as in Space!!!

ArduPilot Board with ATMega1280 microcontroller

IMU with accelerometers, gyros,
static pressure sensor and USB

IMU mounted on mainboard

GPS Receiver

Dynamic pressure sensor (difference between total
and static pressure)

Milling "StageI-Prototypes"

The following pictures contain some impressions from building the first two “StageI-Prototypes” in the “Akamodell” workshop. We milled them out of styrofoam blocks,
which is a cheap and fast way to get some flying models for autopilot development.

Nevertheless, due to the complex shape the milling needed certain thoughts to get it done. The way we did it, was to first mill the bottom side, followed by milling a tray with exact the negative shape of the bottom side. The upper part can be milled by placing the styrofoam block with its bottom side in the perfectly fitting tray. Holes in the tray, all connected to vacuum cleaner, suck the block downwards and thereby preventing it from moving during milling.
Another challenge was not to crash the milling head. As you can see in the pictures it gets from time to time quite cozy between the model and the head following the desired contour.